Possible reference to Marylebone. See COVE Master Map entry on Marylebone: 

https://editions.covecollective.org/place/marylebone

In London Labour and the London Poor edition: 

Phase 1

Of Groundsel and Chickweed Sellers. (Volume 1): "Low Marrabun I goes to always of a Saturday and Wednesday. . . . I does High Marrabun on a Friday, because I aint able to do so much on that day, for I gathers my stuff on the Friday for Saturday. I find Low Marrabun the best of my beats. I cry ‘chickweed and grunsell’ as I goes along."